How to Calculate & Analyze Your Electric Bill

How to Calculate & Analyze Your Electric Bill
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Figuring out how your electric bill is calculated by your utility company is a simple matter; analyzing your energy consumption is more complex. It involves taking stock of when and how you use energy. These details likely won't come from the bill -- you'll just see a total usage figure. You can register with your energy company to access a online usage monitor or tracker that allows you to see when and where you use power. By studying the numbers, graphs and charts generated by the monitor or tracker, you can better understand how to prepare for power bill spikes or make changes to your home or lifestyle habits .

The Measure of Consumption

Generally, your electric bill is the product of kilowatt hours multiplied by the rate which, depending on your power company, can be tiered by how many kilowatt hours you use. The kilowatt hour (kWh) measures your energy use and comes from the readings on the meter attached to your home. Your kilowatt hours are based on the wattage of each item that draws power multiplied by the number of hours that item is used each month, with the product divided by 1,000. This is because a kilowatt has 1,000 watts.

The Power Grabbers

Online power trackers can show you what percentage of your energy use -- and bill -- come from particular appliances or systems in your home. Much of your bill is courtesy of your heat pump or furnace. According to the U.S. Department of Energy, heating accounts for 42 cents on every dollar on electric bills. To reduce running times, keep your home insulated and close air leaks around walls, ceilings, windows and light switches. reports that these measures can trim your bill by a range of 5 to 30 percent. To decrease usage for lighting, install dimmers or sensors and use lower-wattage bulbs. You can find the wattage on a bulb or unit's label, or go to to find the wattage. For example, a clothes dryer uses between 1,800 and 5,000 watts; at the high end, one hour of use translates to two kilowatt hours.,

By Day or Month

Look on your company's online tracker to see how much power you use daily or monthly; your bill likely does not show day-to-day use. You may notice higher energy consumption on, for instance, days where you used appliances or lights for many hours because of entertaining guests or days or weeks of cold weather. See if your company can tell you the weather on each day in the billing cycle, so you can see how your energy use is affected by weather.

Power By the Hour

Online monitors from your power company can even break down usage by the hour. See if you're using power during times you are asleep or not at home, such as by leaving a light, television or computer running. For example, you can consume 0.96 kilowatts by forgetting to turn off your 120-watt flat screen before you embark on eight hours of sleep or an eight-hour work day.